At present, to emit signals in the hectometric waveband, isolated radiating masts of very great height, of the order of 20 to 200 meters, are generally installed far away from towns and broadcast relatively high powers. If it is required to install a mast of this kind near a built-up area or in a town, a large area must be available, for safety reasons in particular, for erecting the radiating mast and installing the ground network associated with the mast and comprising a plurality of wires placed on the ground or buried at a shallow depth in the ground. Consequently, to install a mast type antenna, it is necessary to obtain land for it, the necessary government permits, and the approval of immediate neighbors.
Moreover, a mast type antenna is not able to multiplex a plurality of emission signals with different frequencies at high power; for example, it is not possible to multiplex emission signals with high power differences, for example one at 300 kW and another at 1 kW.